Bad sex?

My husband says that he loves having sex with me and that the sex is good. Well when we have sex he just lays there doing nothing. It’s like he is sleeping. He keeps his eyes closed and doesn’t even make a sound. I feel like he is imagining fucking someone else when he is fucking me. I am always on top. He won’t be on top or do any other positions. I have talked to him about it and he always makes lame excuses.